open-flame device is ducted straight from outside to
the device; or the alarm relay from the detector is
used to automatically shutdown the combustion
process in the event of refrigerant leakage.
Indicate all applicable alarm controls on the
drawings.
Delete the information in the last bracketed
sentence if an EMCS is not applicable to the design.
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Detector shall be the continuously-operating, halogen-specific type.
Detector shall be appropriate for the refrigerant in use. Detector shall
be specifically designed for area monitoring and shall include [a single
sampling point] [[_____] sampling points] installed where indicated.
Detector design and construction shall be compatible with the temperature,
humidity, barometric pressure and voltage fluctuations of the operating
area. Detector shall have an adjustable sensitivity such that it can
detect refrigerant at or above 3 parts per million (ppm). Detector shall
be supplied factory-calibrated for the appropriate refrigerant. Detector
shall be provided with an alarm relay output which energizes when the
detector detects a refrigerant level at or above the TLV-TWA (or toxicity
measurement consistent therewith) for the refrigerant in use. The
detector's relay should be capable of initiating corresponding alarms and
ventilation systems as indicated on the drawings. Detector shall be
provided with a failure relay output that energizes when the monitor
detects a fault in its operation. [Detector shall be compatible with the
facility's energy management and control system (EMCS). The EMCS shall be
capable of generating an electronic log of the refrigerant level in the
operating area, monitoring for detector malfunctions, and monitoring for
any refrigerant alarm conditions.]
2.14
REFRIGERANT RELIEF VALVE/RUPTURE DISC ASSEMBLY
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NOTE: ASHRAE 15 requires refrigeration systems to
be protected with a pressure-relief device that will
safely relieve pressure due to fire or other
abnormal conditions. A relief valve/rupture disc
assembly is the optimum solution. The rupture disc
will provide visual indication of a release while
also providing immediate shutoff once a safe
pressure is achieved.
Designer will indicate on the drawings the location
of each new relief valve/rupture disc assembly as
well as the routing and size of corresponding
pressure-relief piping. The routing and size of new
pressure-relief piping will be per ASHRAE 15.
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The assembly shall be a combination pressure relief valve and rupture disc
designed for refrigerant usage. The assembly shall be in accordance with
ASME BPVC SEC IX and ASHRAE 15. The assembly shall be provided with a
pressure gauge assembly which will provide local indication if a rupture
disc is broken. Rupture disc shall be the non-fragmenting type.
SECTION 15652A
Page 29
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